Answer:
2 CDs and 6 movies
Step-by-step explanation:
Let the number of CD you bought be x, and the number of movies you bought be y.
Since you bought 8 items in total,
x + y = 8 ______(1)
The sum of money spent is 78, so
9x + 10y = 78 ________(2)
From equation (1),
x = 8 - y ________(3)
Substitute (3) into (2),
9 (8-y) + 10y = 78
72 - 9y + 10y = 78
- 9y + 10y = 78-72
y = 6
Now substitute y=6 into (3).
x = 8 - y
x = 8-6
x = 2
Therefore, you bought 2 CDs and 6 movies.
